1. Field
A stator arrangement, or distributor, of a turbine machine, for example, of an exhaust gas turbine or a compressor is disclosed. In an exhaust gas turbine which is exposed to axial incident flow, such a distributor is connected upstream of the moving blades of the turbine and has guide blades in the exhaust gas-carrying flow channel which are arranged axial-symmetrically to the turbine axis and which can each be pivoted around a radially guided axis, and a pivoting device which moves the guide blades around the pivot axis. With this distributor, by pivoting the guide blades, the size of the cross section area of the flow channel through which the exhaust gas flows can be changed and the exhaust gas turbine can be adapted to changing exhaust gas flows, as occur for example in partial load operation of an internal combustion engine which delivers an exhaust gas.
2. Background Information
A distributor is described for example in DE 100 13 335 A1. In this distributor, concentrically to the moving wheel of the turbine there is a setting ring which is located radially outside in the flow channel. A blade shaft which is guided out of the flow channel through the housing wall radially to the outside is attached to each of the guide blades. The blade shaft is supported to pivot around the pivot axis with its part which is guided to the outside. The pivoting device contains a setting ring which is located outside the flow channel and which can be pivoted around the turbine axis, and adjusting levers which transmit torque from the setting ring to the blade shaft of each guide blade.
The adjusting levers are slipped with one end onto the blade shaft. With the other end the adjusting levers are guided in the grooves of the setting ring. The grooves are bordered by two radially guided groove walls, with a distance from one another which is somewhat greater than the diameter of the ends of the adjusting levers, which ends are made as a ball head and are guided in the grooves.
Due to the rotational and pivoting motion, the ball head of the adjusting lever is moved on the surface of the groove walls. Based on the point support of the balls in the grooves of the adjusting lever, very high Hertzian stresses can occur in spite of moderate normal forces. The relative movements of the balls on the surface of the groove walls and the high surface pressures can lead to wear on the sliding partners in operation.
Patents U.S. Pat. No. 5,316,438 and U.S. Pat. No. 4,867,635 and patent disclosure document DE 1 503 527 A1 disclose distributors with adjustable guide blades. The adjustment mechanisms of these distributors have adjusting devices which transmit force from a setting ring to the shafts of the guide blades to adjust the guide blades. The adjusting levers are provided on one end with a ball head and engage ball sockets with it in the region of the setting rings.